The present invention relates to a hand tool, and more particularly to an adapter for connecting the hand tool with a socket. The adapter has double cam sections so that a user can operate the adapter by small angle for engaging the adapter with the socket or releasing the socket.
A conventional wrench is often fitted with a socket for driving a nut. In order to fit with sockets with different sizes, the wrench is equipped an adapter. The adapter has a projecting post. A ball member is inlaid in a lateral wall face of the projecting post. A spring is disposed in the projecting post for pushing the ball member to partially protrude out of the projecting post. When the projecting post is fitted with the socket, the ball member abuts against the inner wall of the socket to prevent the socket from detaching from the adapter. However, in the case that the spring has greater resilience, it is necessary for a user to exert a greater force for fitting or taking off the socket. In the case that the spring has less resilience, the ball member will be unable to effectively hold the socket and the socket is likely to detach from the adapter.
In order to solve the above problem, an improved adapter has been proposed. Referring to FIGS. 1 and 2, the adapter 10 includes: a main body 12 formed with an axial fitting hole 13 and a shaft hole 14; a pressing rod 15 fitted in the shaft hole 14 and upward pushed by a spring 16, the wall face of the pressing rod 15 being formed with a concave section 17; a rotary bar 18 transversely passing through the main body 12 and having a rotary button 19, the rotary button 19 being manually rotatable for turning the rotary bar 18, the body of the rotary bar 18 being formed with a cam section 20; and a ball member 22 positioned in a through hole 24 of the main body and pushed by the pressing rod to protrude out of a projecting post 25 of the bottom end of the main body.
In use, the projecting post 25 is fitted with the socket. As shown in FIG. 2, the pressing rod 15 is positioned at an upper dead end and free from the pressing of the cam section 20. At this time, the ball member 22 abuts against the inner wall of the socket without retraction so that the socket is effectively held. When taking off or fitting the socket, the rotary button 19 is rotated to turn the rotary bar 18. As shown in FIG. 3, the cam section 20 presses down the pressing rod 15 to slide downward. At this time, the ball member 22 can move into the concave section 17 and retract into the through hole 24. Under such circumstance, the socket is no more engaged with the ball member and can be taken off.
According to the above arrangement, a user can operate and control the position of the ball member so as to facilitate taking off or fitting of the socket and thus solve the problem of the conventional adapter. However, such structure still has some shortcomings as follows:
First, as shown in FIG. 3, only when the cam section is faced downward, is the pressing rod pressed down by the rotary bar to release the socket. While at other angular positions, the rotary bar is unable to press down the pressing rod. When a user rotates the rotary bar 18 to leave the position of FIG. 3, the cam section 20 no more presses down the pressing rod 15. After the rotary bar is released, the rotarybar can be positioned at any angular position. FIGS. 4 and 5 show two of these angular positions. In FIG. 4, a user needs to clockwise rotate the rotary bar by 270 degrees for making the cam section press down the pressing rod. In FIG. 5, no matter the user clockwise or counterclockwise rotates the rotary bar, the user must rotate the rotary bar by 180 degrees to depress the pressing rod. Therefore, with such structure, it is necessary to rotate the rotary bar by large angle for depressing the pressing rod. Such operation is inconvenient for a user to perform.
Second, when the pressing rod is positioned at the upper dead end, the rotary bar may be positioned at any angular position. In other words, the rotary bar has no specific location point. Therefore, it is hard for a user to know by how many degrees the rotary bar should be rotated for pressing down the pressing rod.
In addition, in the conventional structure, the rotary button 19 protrudes from the main body 12. A user often incautiously gets injured by the protruding rotary button 19.